Conventionally gable-top paper containers are widely used as containers for milk, juice, and the like. The gable-top container is set up by closing the bottom of the prismatic barrel flat, and sealing the top into a gable after the container is filled with contents, such as a liquid. To open this paper container, an operation of first splitting one sealed part of the top seal, horizontally pulling the one sealed part and the other sealed part of the top seal, causing the inner seal to split open, and pulling up the folded-in sealed parts of the inner seal is needed. But seal strength of the top seal is so high that such opening operation is difficult. To facilitate the opening operation, paper containers with various extra tab members provided on one of the folded-in top panels participating in forming the opening have been proposed (e.g., Japanese Utility Model Laid-Open Publication No. 128931/1988, Japanese Utility Model Laid-Open Publication No. 66423/1990, etc.).
In the paper container of the type described in Japanese Utility Model Laid Open Publication No. 128931/1988, since a tab member is partially secured to one folded-in top panel, attachment of the tab is not easy. This is a problem. In the paper container of the type described in Japanese Utility Model Laid-Open Publication No. 66423/1990, the tab member is an obstacle to forming the container, thus causing troubles. This is a problem.